Overmolding

The overmoulding process involves creating a single part using a combination of two or more plastic or elastomer materials. During the plastic overmoulding process, the base layer part is moulded first, then the additional plastic layer(s) are moulded over and around the original part. One or more plastic resins may be used depending on material compatibility to achieve a specific texture or look.

Overmoulding is used for a range of applications including medical, automotive, military and more. A common example of injection overmoulding is a toothbrush with a stiff frame and rubberised grips on the handle. Different overmoulding material options are also used to add colour contrast for aesthetics or to create flexible areas on rigid components.

The difference between overmoulding and multi-injection is that the preform substrate is moulded in a previous operation. This is then loaded into a second tool (or tool cavity) and the overmoulded material is added.

Through this method a bi-material component can be produced using a standard single barrel injection moulding machine.